Filling And Evolving Of Mesozoic Basin In Chengde District And Its Delationship With Tectonics

The relationship between the basin and erogenic systems is one of the frontier research fields in the study of continental geodynamics. The basin and mountain systems are two basic and essential tectonic units, which are developed in the temporal and spatial evolution of the crust.Basin system is the united area of the deposition space and the denudation area. The evolution of the basin system can mirror the process of the related erogenic movement. The disintegration of a basin system indicates the end of one time of erogenic movement. And then a new basin system comes into being. The Yanshan erogenic belt is a Mesozoic intracratonic erogenic belt. There are several basin-mountain transforming processes in the orogeny, and this paper will discuss this process based on basin evolution.During my Master' degree investigation, I mainly focused on the coarse-grain stratigraphy within Mesozoic basins in Chengde and Pingquan districts, the eastern Yanshan, and did systemic provenance analysis and paleo-current direction measurement and studied the relationship among basin evolution, volcanism and tectonism. Then I summarized the Mesozoic basin development and the coupling characters of basin and mountain. The evolution of basin and mountain in this area can be divided into several stages: the stage of compression uplift and flexural basin during the Triassic through the Early Jurassic, the stage of structural compression-volcanism and foreland basin during the Middle and Late Jurassic and the stage of rift basin in the Cretaceous.During this study, the concept of provenance phase is proposed. It means a generalization for the characteristics of the lithology, stratigraphy, tectonics, weathering and erosion in the provenance, which are reflected by the sediments of basins. In order to analysis the paleo-current effectively on the conglomerate, I proposed a method that can be carried out by orthogonal photo in field and statistic analysis at room. It has been improved to be efficient and veracity, especially for the case that the states of gravels can not be measured directly.